Projector systems are generally devices that integrate light sources, optics systems, electronics, and light modulators for projecting data such as images, video, documents, and spreadsheets from computers or video devices onto walls or front or rear screens, for large-image viewing. They are especially popular among business users who give presentations as part of their job responsibilities. Newer projectors can weigh as little as a few pounds, making them well suited for business travelers. As the quality of projection technology has improved, projectors are also finding their way into peoples' homes for high-definition television (HDTV) and other home entertainment applications. Some industry pundits predict that digital projectors will also become the standard projection technology used in movie theaters.
A projector commonly includes a light source, such as a light bulb, that is a high-temperature component of the projector. The light bulb is a high-temperature component in that it operates at a high temperature. For instance, the outer envelope of the burner of the light bulb can reach approximately 950° C., for long lengths of time. The useful lifetime of the light bulb is commonly considered to be measured as the length of time the projector of which it is a part is operating. However, more accurately, the useful lifetime of the light bulb is measured as the length of time it is operating at a high temperature. When the useful lifetime of the light bulb has expired, it usually needs to be replaced with a fresh bulb in the projector in order for the projector to continue performing optimally. One definition of end of bulb life is when light output is at fifty percent of its initial value.